1. Field of the Invention
This invention relates to a connector housing and a connector, and more particularly to a connector housing and a connector, in which a metal terminal is retained by a retaining arm (lance) formed within the connector housing.
2. Description of the Related Art
There has heretofore been used a technique in which a male connector and a female connector, each having metal terminals beforehand received in its connector housing, are fitted together, thereby connecting the metal terminals of the male connector respectively to the metal terminals of the female connector. For example, as disclosed in Patent Literature 1, cantilever-like retaining arms (called “lances”) for retaining the metal terminals respectively at predetermined positions within the connector housing are formed within the connector housing, and each metal terminal is retained by a convex lance beak formed at a free or distal end portion of the retaining arm.
FIG. 1 is a cross-sectional view of a conventional connector housing 110 analogous to the connector housing disclosed in the above Patent Literature 1. FIG. 2 is a perspective view roughly showing the construction of a female metal terminal 80 to be received in the connector housing 110. Although the front, rear, right and left sides are set as shown in the drawings for description purposes, this may actually be changed. This can be applied also to FIG. 4 referred to later. A pair of upper and lower receiving chambers 120 for receiving the metal terminals 80 are formed within the connector housing 110. A male terminal insertion hole 124 is formed at the front side of each receiving chamber 120. Here, description will be made of the case of inserting the metal terminal 80 into the upper receiving chamber 120. A lance 150 is formed on and extends forwardly (left in the drawings) from a generally central portion of a receiving chamber partition portion 130 separating the pair of upper and lower receiving chambers 120 from each other. A rear half portion of the receiving chamber partition portion 130 disposed at the rear side of the lances 150 is thick, while a front half portion thereof is made thin to provide spaces (designated by reference numeral 121 only in FIG. 1A) each for allowing the lance 150 to be elastically bent in the upward-downward direction. The metal terminal 80 includes a barrel portion 81 having a cable W fixedly connected thereto by crimping or press-clamping, and a connection portion body 90. The connection portion body 90 has a generally box-shape, and a male terminal (not shown) can be inserted into the connection portion body 90 through a front open end thereof. A guide groove 95 is formed a lower wall 98 (FIG. 1A) of the connection portion body 90, and extends in the forward-rearward direction as shown in FIG. 2. A beak retaining hole 94 is formed at a generally central portion of the guide groove 95, and a lance beak 54 (described later) is adapted to be retainingly engaged in this beak retaining hole 94.
FIGS. 3A to 3D show the lance 150. FIG. 3A is a perspective view of the lance 150, FIG. 3B is a perspective view schematically showing the lance 150, FIG. 3C is an enlarged view of a region Y1 of FIG. 1A, and more specifically is a side-elevational view of the lance 150, and FIG. 3D is an enlarged view of a region Y2 of FIG. 1B, and more specifically is a side-elevational view of the lance 150, showing a condition in which the metal terminal 80 abuts against the lance beak 153. The lance 150 can be elastically deformed in the upward-downward direction so as to effectively achieve the insertion and fixing of the metal terminal 80. More specifically, the lance beak 153 having a trapezoidal vertical cross-section is formed on a front end portion of a lance base 151 of a generally rectangular parallelepiped shape extending from the thickened portion of the receiving chamber partition portion 130. Further, the lance 150 has a front free end 152 formed at the front side of the lance beak 153. The lance beak 153 disposed in the upper receiving chamber 120 is upwardly convex, while the lance beak 153 disposed in the lower receiving chamber 120 is downwardly convex. The lance 150 has a lance guide 154 of a predetermined height and a predetermined width extending from its proximal end portion to the lance beak 153.
The metal terminal 80 is inserted into the receiving chamber 120 from the rear side of the connector housing 110, and is moved forward with the lance guide 154 fitted in the guide groove 95 of the connection portion body 90. Then, a front end 91 of the metal terminal 80 is brought into abutting engagement with the lance beak 153 as shown in FIGS. 1B and 3D, and then the metal terminal 80, while elastically bending the lance 150 downwardly, further moves to an inner end portion of the receiving chamber 120 as shown in FIG. 1C, so that the lance beak 153 is retainingly engaged in the beak retaining hole 94 formed in the connection portion body 90, thereby fixing the metal terminal 80 to the connector housing 110.
Patent Literature 1: JP-UM-A-50-113881
With respect to the shape of the lance 150, in the case where the angle of inclination of a slanting surface 161 of the lance beak 153 is large, the front end 91 of the inserted metal terminal 80, when abutting against the lance beak 153, is sometimes caught by this lance beak 153 at an abutting point P1 (see FIG. 3D), so that the metal terminal 80 can not advance any further, thus inviting a condition of so-called striking abutment. At this time, a load several times larger than the force of insertion of the metal terminal 80 acts on the lance beak 153, and the operation for inserting the metal terminal 80 has sometimes been retarded. Usually, about one second is required form inserting the metal terminal 80, but when the striking abutment occurs, about 10 seconds have often been required, thus much lowering the efficiency of the operation. In some cases, the metal terminal 80 fails to be completely inserted, or the lance 150 is shaved by the metal terminal 80, so that incomplete electrical connection may be caused by resulting shavings. Therefore, it has been desired to provide a technique for improving these points.